By utilizing their small thickness and low power consumption, liquid crystal display devices have been conventionally widely used as displays for televisions, personal computers, mobile telephones, PDAs (Personal Digital Assistants), and the like.
Active matrix drive liquid crystal display devices include an active matrix substrate on which a plurality of pixel electrodes and a plurality of TFTs (Thin Film Transistors) are formed, a counter substrate which faces the active matrix substrate and on which a common electrode is formed, and a liquid crystal layer which is enclosed between the two substrates and inside a frame-like sealing member. Active matrix drive liquid crystal display devices have a display portion which includes a plurality of pixels and displays an image.
As an arrangement of pixels constituting the display portion, the delta arrangement, which is suitable for displaying of moving images, is known (see, for example, Patent Document 1). FIG. 11 is an enlarged plan view schematically showing a portion of a conventional active matrix substrate of a liquid crystal display device having a delta arrangement. Note that, in FIG. 11, and FIG. 12 described below, wires 103 and 104 and TFTs 105 are seen through an insulating film 106.
As shown in FIG. 11, on the active matrix substrate of a liquid crystal display device having a delta arrangement, pixel electrodes 101 constituting pixels are provided in a delta arrangement. The pixel electrodes 101 are arranged in lines which define a plurality of rows 102. The pixel electrodes 101 in adjacent rows 102a and 102b are offset by half a pitch from each other in the row direction (the horizontal direction in the figure). As used herein, the terms “horizontal,” “vertical,” “left,” “right,” “upper,” “lower,” “upward,” and the like refer to the same directions as appearing in the accompanying drawings.
Moreover, a plurality of gate lines 103 extending parallel to the rows 102a and 102b, and a plurality of source lines 104 extending in a direction intersecting the gate lines 103 while alternately turning left and right, are each formed between the corresponding pixel electrodes 101.
TFTs 105 are connected to the respective pixel electrodes 101. The insulating film 106 is provided on the TFTs 105. Drain electrodes 107 of the TFTs 105 are connected to the respective pixel electrodes 101 via respective contact holes 106a formed in the insulating film 106. Each of the TFTs 105 is provided in the vicinity of an intersection portion of the corresponding gate line 103 and source line 104 for the purpose of increasing the aperture ratio of each pixel.
Each source line 104 has a plurality of first linear portions 104a extending along left sides of the respective pixel electrodes 101, and a plurality of second linear portions 104b linked to the respective first linear portions 104a and extending along upper and lower sides of the respective pixel electrodes 101 to middle portions of these sides. A protruding portion 104c extending along the upper or lower side of the corresponding pixel electrode 101 is provided at one end of every other second linear portion 104b of each source line 104. Each TFT 105 is alternately connected to the corresponding protruding portion 104c and to the corresponding second linear portion 104b along the corresponding source line 104. Thus, the active matrix substrate has a non-inverted structure in which the TFTs 105 connected to the respective pixel electrodes 101 are located at the same position in the respective pixel electrodes 101.
In delta-arrangement liquid crystal display devices having such a non-inverted structure, even if regions constituting pixels of the active matrix substrate and the counter substrate are offset from each other, the overlapping area between each color filter and the corresponding pixel electrode is the same for corresponding pixels on adjacent rows, and therefore, a horizontal stripe pattern or roughness is not likely to occur in displayed images.